1. Field of the Invention
The present invention relates to a terminal to be connected to covered electric wires, particularly to a terminal to be connected to the covered electric wires without feazing or bending exposed core wires, more particularly to a terminal preventing core wires from being cut when the core wires are depressed with pressure, and further particularly to a terminal for a waterproof agent to penetrate below core wires uniformly.
2. Description of the Related Art
In an assembly of a wiring harness, an insertion of covered electric wires to a terminal or the fixing of the terminal is carried out manually with hand tools or swaging machines. Problems arising at the assembly are explained by referring to drawings.
FIG. 7 is a perspective view to explain a conventional terminal and an insertion of covered electric wires. FIG. 8 is a sectional view of FIG. 7 and a drawing to explain problems of the conventional type.
As shown in FIGS. 7 and 8, a plurality of covered electric wires 2 with a prescribed length of core wires 22 exposed by removing covers 21 are inserted into a sleeve terminal 9. Since there are many core wires 22 in the each covered electric wire 2, the covered electric wires are inserted into the terminal 9 in an arrow direction without feazing or bending the core wires 22.
JP,2005-197159,A discloses a prior art of an insertion method of covered electric wires.
As shown in FIG. 8, the conventional terminal 9 has a small opening G with a planar insertion edge 91 so that it is quite difficult to insert the core wires 22 into the terminal 9 without feazing or bending them.
Accordingly, when the core wires 22 are inserted into the terminal 9, it is necessary to watch around the insertion edge 91 for the core wires 22 not to feaze or bend so that the handling is quite difficult and the workability is reduced. Furthermore, the feazing and bending of the core wires 22 cause an increase of electric resistance or a decrease of fitting strength, resulting to a low reliability of connection.
FIG. 16 shows a perspective view of a conventional terminal. FIG. 17 shows a problem of the conventional terminal. Reference numerals in FIG. 17 correspond with those of FIG. 16.
As shown in FIG. 16, the conventional terminal 9′ includes an electric connection portion 92′ having an insertion through-hole 93′ at a front side to connect a terminal of electric instruments and upright segments 91′ at a base side to fix covers 21′ of covered electric wires 2′. Core wires 22′ exposed from the covers 21′ with a prescribed length are thermo-compression bonded or ultrasonic bonded to the terminal 9′ with an electrode or horn.
JP,H10-125363,A discloses a prior art related to the conventional terminal.
As shown in FIG. 17, when a front portion of the core wires 22′ is pressure-bonded to the terminal 9′ as shown by a large arrow, the core wires 22′ near to and in an upper position of the covers 21′ are pulled rapidly in a slim arrow direction. Accordingly, the upper portion of the core wires 22′ is forced to deform and is cut. The problem often occurs when the covers' 21 are thick or a large number of the covered electric wires 2′ are utilized so that a difference of outer diameters between a bundle of the core wires 22′ and a bundle of the covers 21′ is large. The cutting of the core wires 22′ increases electrical resistance and decreases the fixing strength, resulting to a decrease of connection reliability.
In an assembly of a wiring harness, after covered electric wires are inserted into a terminal and fixed with upright segments, a waterproof agent is applied to the terminal. There is a problem in a conventional assembly as described below.
FIG. 24 is a perspective view of a conventional terminal. FIG. 25 is an illustration explaining the problem. The reference numerals of FIG. 24 correspond with those of FIG. 25.
As shown in FIG. 25, the conventional terminal 9″ includes an electric connection portion 92″ having an insertion through-hole 93″ at a front side to connect a terminal of electric instruments and upright segments 91″ at a base side to fix covers 21″ of covered electric wires 2″.
In order to obtain a waterproof of the terminal 9″, the core wires 22″ of the covered electric wires 21″ are covered with a heat shrinkable tube 99″ with a hot-melt adhesive as shown in FIG. 25. The hot-melt adhesive is melted with a heat treatment and the waterproof agent penetrates into gaps among the core wires 22″.
JP,H10-125363 discloses a prior art related to a waterproof of a terminal.
The hot-melt adhesive covers around the terminal 9″ but does not penetrate between the core wires 22″ and a terminal base plate shown by an arrow of FIG. 25. Hence, the satisfactory waterproof between the core wires 22″ are not attained in the structure of the conventional terminal 9″.